If they once reached Sir James Peel Edgerton in safety, all would be well.  But would they reach him?  Would not the silent forces of Mr. Brown already be assembling against them?  Even that last picture of Tommy, revolver in hand, failed to comfort her.  By now he might be overpowered, borne down by sheer force of numbers....  Tuppence mapped out her plan of campaign.

As the train at length drew slowly into Charing Cross, Jane Finn sat up with a start.

“Have we arrived?  I never thought we should!”

“Oh, I thought we’d get to London all right.  If there’s going to be any fun, now is when it will begin.  Quick, get out.  We’ll nip into a taxi.”

In another minute they were passing the barrier, had paid the necessary fares, and were stepping into a taxi.

“King’s Cross,” directed Tuppence.  Then she gave a jump.  A man looked in at the window, just as they started.  She was almost certain it was the same man who had got into the carriage next to them.  She had a horrible feeling of being slowly hemmed in on every side.

“You see,” she explained to Jane, “if they think we’re going to Sir James, this will put them off the scent.  Now they’ll imagine we’re going to Mr. Carter.  His country place is north of London somewhere.”

Crossing Holborn there was a block, and the taxi was held up.  This was what Tuppence had been waiting for.

“Quick,” she whispered.  “Open the right-hand door!”

The two girls stepped out into the traffic.  Two minutes later they were seated in another taxi and were retracing their steps, this time direct to Carlton House Terrace.

“There,” said Tuppence, with great satisfaction, “this ought to do them.  I can’t help thinking that I’m really rather clever!  How that other taxi man will swear!  But I took his number, and I’ll send him a postal order to-morrow, so that he won’t lose by it if he happens to be genuine.  What’s this thing swerving——­Oh!”

There was a grinding noise and a bump.  Another taxi had collided with them.

In a flash Tuppence was out on the pavement.  A policeman was approaching.  Before he arrived Tuppence had handed the driver five shillings, and she and Jane had merged themselves in the crowd.

“It’s only a step or two now,” said Tuppence breathlessly.  The accident had taken place in Trafalgar Square.

“Do you think the collision was an accident, or done deliberately?”

“I don’t know.  It might have been either.”

Hand-in-hand, the two girls hurried along.

“It may be my fancy,” said Tuppence suddenly, “but I feel as though there was some one behind us.”

“Hurry!” murmured the other.  “Oh, hurry!”

They were now at the corner of Carlton House Terrace, and their spirits lightened.  Suddenly a large and apparently intoxicated man barred their way.

“Good evening, ladies,” he hiccupped.  “Whither away so fast?”